1. Field of Invention
The invention relates generally to motorized vehicles having a clutch. More particularly, the invention relates to motorized track-driven vehicles, such as snowmobiles, that utilize clutches for a continuously variable transmission.
2. Prior Art
Vehicles use a wide variety of transmissions for vehicle propulsion. A type of transmission widely used in smaller vehicles, e.g., snowmobiles, go karts and all-terrain vehicles (ATVs), is an endless belt transmission; often referred to as a continuously variable transmission (CVT). In a CVT, both outward torque and speed varies substantially continuously, i.e., without gearshifts, over the entire speed range of the engine. A CVT typically includes a driving clutch with a shaft that is coaxial with the output shaft of the vehicle's engine. The driving or primary clutch includes a stationary sheave and a movable sheave that together define a pulley around which a transmission belt travels. The belt also travels around a driven or secondary clutch that transfers power from the driven clutch to the vehicle track or wheels. The driven clutch also includes a stationary sheave and a movable sheave that define a pulley.
Continuously variable transmissions typically are operated at high RPMs. As a result, the area around the drive and driven clutches and the transmission belt is hazardous and is therefore covered to prevent inadvertent contact by a person or object. Clutch shields are commonly used for covering clutch and belt components of a CVT. Known clutch shields generally include a piece of sheet metal formed to cover a portion of the CVT and are secured to the vehicle frame with removable fasteners or hinges that allow the shield to be temporarily moved out of the way while accessing the CVT. A disadvantage of many clutch shields is that the shield is awkward or time consuming to remove because of the fasteners that are used to attach the shield to the vehicle. A disadvantage of clutch shields that are hinged to the vehicle is that the shield moves in only one plane of motion, and as a result, moves into an inconvenient position or does not move far enough out of the way to easily access the CVT.